In a sense, their true enemy was less America than an arrogant future to which a vain country lay claim. This was a country that named the previous hundred years the American Century. So as much as the 19 men, who commandeered four airliners nine months, eleven days, and nine hours into the next century, despised America—despised its "pure products [that] go crazy," as William Carlos Williams described them, including a rowdy pluralism, a heedless innovation, an irreverent culture, and a reckless dream that the country named as surely as it named centuries—these men despised the way such American things were expressions of the modern age. They flew those airliners into the clock of the new century to shatter its face, wreck its watchworks, still its hands, and blast into space its numbers, and in every way that they meant to succeed, they failed. Whether they succeeded in other ways that matter more remains to be seen.

America gets the politics it deserves more than we know. A nearly mystic sense of destiny seems to shape our history, which is how a nation ready to resolve at such a cost to itself the matter of freedom and slavery, for instance, could produce a president at once as unlikely and as exquisitely suited to the moment as Abraham Lincoln. After September 11, 2001, the enduring cliche was that everything to which our history has led us was changed and never would be the same. A more unsettling truth is that too many of the wrong things changed and not enough of the right ones, that opportunities for change presented themselves that we failed to seize and our politics refused to accommodate, all of which says more about us than about 19 mass murderers who thought if they just got through those last few bad seconds, they'd wake up in the Playboy Mansion. Most obviously, post-9/11 America is a story of two presidencies: the one concurrent with 9/11 and the one that followed. But for the attacks, the first wouldn't have unfolded as it did, and the second wouldn't have happened at all.

Many things came down that day with its planes and buildings. Among them were all the caveats attached to George W. Bush's presidency. Twenty years ago, long enough that a political generation remembers nothing else, the country began sliding into an era of presidencies perceived by a large segment of the public as illegitimate, in the aftermath of the era's first overtly ideological White House, Ronald Reagan's. As it does in many instances, ideology has a way of insisting on the invalidity of whatever doesn't acquiesce to it, and the 1988 victory of the elder Bush, who translated Reaganism into the vernacular of "values," over a hapless Massachusetts governor who disowned liberalism and ran on "competence," left a large segment of voters bitter and furious about a campaign that was even shabbier than the usual garden-variety electoral shabbiness. A failure to win a majority of the 1992 and '96 vote, along with a political identity formed in a decade as disreputable as the '60s, so tainted Bill Clinton's presidency in the eyes of his adversaries that they insinuated he had committed murder from Little Rock to the White House. With George W. Bush's election, innuendo became institutionalized. The popular tally that favored Bush's opponent and the partisan nature of the Supreme Court decision that ratified the election left more than half the country looking at the presidential seal and—without having to squint or move too much to one side or the other—seeing an elaborate asterisk.

On September 10, 2001, the only thing about Bush's presidency as noteworthy as how he won it was its belligerence. This included the defunding of international family-planning organizations that merely informed women of the right to an abortion, desertion of the Kyoto treaty to reduce greenhouse-gas emissions, and the decision, opposed even by Reagan's family as the former president was ravaged by dementia, to cease federal support of stem-cell research. The Bush presidency responded to the controversy of which it was born with a siege mentality and the resolve to take its mandates where it could find them. Bush himself may never have understood the extent to which he was a prisoner of the circumstances in which he was elected. Had he been elected outright by a nation more forgiving, he might have been a more forgiving president. The asterisk that weighed down his presidency was another of September 11's casualties, and as his presidency was renewed, so was the way the rest of us regarded it.

***

IF THE CHANCE CAME SOONER than he was ready for it, no president ever was provided the occasion that George Bush was to reinvent himself. Bestowed by 90 percent of the country with heroic status within days of the cataclysm, he suddenly was bigger than his advisers, bigger than his vice president, bigger than his father, beside whom he always had been fated to be smaller, bigger than his own self that maybe he knew well and maybe he didn't. It's not that Bush lacked the brains or good intentions to re-examine his place in the scheme of things. It's that his temperament and maybe his religious deliverance from a more callow life were contingent on a hostility to doubt, that most abhorrent of traits in the eyes of the congregation but the antivirus to hubris in the body politic. What made Bush the right president for 9/11 in the short run was what made him the wrong president in the long run. Naturally he never was going to turn into Theodore Roosevelt, transformed by a mere assassination; he never was going to metamorphose into a radical or liberal or anything more outlandish than a moderate conservative. But the path of a single crucial step centerward was opened to Bush, and irrevocably forsaken.

As rhetoric cools with the passage of time, if anything it will be clearer what a debacle was the 2003 invasion and the subsequent eight-year occupation of Iraq, a nation that had nothing to do with 9/11. If anything it will be clearer how intellectually corrupt was the decision-making behind it. In the absence of the 9/11 attacks, the worst foreign adventure in modern American history—the rationale for Vietnam was, in its time, stronger—almost certainly never would have taken place. It would have been a nonstarter with a populace that is never as predisposed to war as politicians like to believe and that even in 9/11's wake was sharply divided. Many questioned the existence of Iraqi superweapons and the prospect of mushroom clouds over Orlando. Those old enough to remember Adlai Stevenson presenting to the United Nations enlarged photos of Soviet missile sites in Cuba in 1962 found underwhelming Secretary of State Colin Powell's U.N. presentation, which consisted of his sincerity, assertions that he himself later called wrong, and a drawing of a truck. Months before the American invasion in March 2003, weapon inspectors returned from Iraq and reported, to White House indifference, the discovery of nothing; and in his State of the Union address to Congress that January, the president of the United States misinformed (to put it politely) senators and representatives as to Iraq's import of uranium yellowcake for the purpose of making nuclear bombs. If it's now known from Bush administration officials such as Powell's chief of staff Lawrence Wilkerson, counterterrorism adviser Richard Clarke, and Treasury Secretary Paul O'Neill that the fix was in on Saddam Hussein before 9/11, it's true as well that exploitation of national tragedy in order to advance a precooked agenda is a tradition honored by time if by nothing and no one else. "Judge whether good enough," Secretary of Defense Donald Rumsfeld scrawled in a memo about the incoming data, not six hours after the attacks, to "hit S.H. ... not only [Osama bin Laden]."

Perhaps to a man who had lost the popular vote and was installed in office by a 5-to-4 court decision, Bush's narrow re-election in 2004—the closest of any since Woodrow Wilson's in 1916—seemed like a step up. The election also was a measure, however, of just how disgraceful the Iraq episode was, and how the president's opportunity to shepherd a traumatized nation to a new unity was wasted. In the years since, the politics that prevailed before 9/11 has grown only more intransigent. In their own ways and to make contradicting points, both hard right and far left conflate the Afghanistan War into the Iraq War, the Afghanistan and Iraq wars into the war against al-Qaeda, and all of them into a "war on terror"; as it happens, none of the 9/11 terrorists was Iraqi or Afghan (most were citizens of what supposedly is the United States' best Arab friend, Saudi Arabia). The right presumes that one antagonistic Middle Eastern landscape is no different from the other, and the left is reflexively antagonistic to any military action at all.

In the brief weeks following 9/11's equal-opportunity slaughter, the word "union" conveyed implications verging on the spiritual. Soon the language of union gave way to a semantics unlike any the country had heard. For the first time in the lives of anyone reading this magazine, maybe for the first time in the life of the republic, the proper relationship of the word "torture" as used in conjunction with the word "America" was seriously debated in the halls of power. Almost as tellingly, "secular" was redefined in a fashion that might be appreciated by Orwell and relished by a onetime speaker of the House and would-be president. One might have expected the word to be championed in the face of an Islamic extremism that detested a Constitution that never mentions, euphemizes, or alludes to God not because its authors didn't believe in such a thing but because they determined believing in such a thing wasn't the Constitution's business. Ten years after 9/11 and that vision of union briefly glimpsed in its awful nova, another Texas governor, recently coveted by the right as a prospective president, would best be known for proposing the possible secession of his state, something that in 9/11's shadow would have sounded obscene if not treasonous.

Now, to some the notion of union is more oppressive than ever. Now, the moment when an American is defined by what he or she believes has given way to the ostentatious flurry of birth certificates that we might pin to our shirts like small flags or hold over our hearts when we pledge allegiance. The very word "country" and what we mean by it is what September 11 changed most of all, as George Bush's successor would learn.

***

Whatever national fate may or may not have been changed by 9/11, individual fortunes surely were. In October 2002, a former first lady elected to the United States Senate and the front-runner for her party's presidential nomination in 2004 (when she didn't run) and 2008 (when she did) voted in favor of a congressional resolution supporting the Iraq War. Nine days earlier and 600 miles way, an obscure biracial, Hawaiian-born Illinois state legislator with a Swahili name gave the first of three speeches that, six years later, would make him president, to the astonishment of maybe even himself.

Even taking into account the romanticism that attends such political junctures, by which every turning point is given the significance of Lincoln at Cooper Union, it's unimaginable that without 9/11 Barack Obama would have become president. Either Hillary Clinton wouldn't have had an Iraq resolution to vote for, or the resolution wouldn't have existed in a context that made an affirmative vote feel so imperative for someone with aspirations to become the first female commander in chief. Not only would Obama's Chicago speech, rejecting not war as a legitimate policy but rather the particulars of this particular war, never have been given but his speech to the 2004 Democratic National Convention in Boston wouldn't have had the same impact. Obama's presidential candidacy would have been preposterous, and thus his March 2008 speech on race, a speech that spoke to a nation's sense of itself at its most profound, in which pointedly the word "union" was resurrected (as in "a more perfect"), wouldn't have come to pass.

All of these speeches directly addressed a post-9/11 America that yearned for that brief few weeks when the country felt, as Obama put it, not like a conglomerate of red and blue states but rather like the United States. Presidents are elected for reasons of default (both Bushes), resume (Eisenhower, Nixon), or message (Reagan, Clinton), and Obama's was the ultimate message candidacy. Though he cast it in terms of "hope" and "change," his message was one of unification, taking on a moral authority it wouldn't have had otherwise, delivered as it was not only with the candidate's eloquence but by someone who, a century and a half ago, would have been in chains on an auction block. More than Bush's, Obama's is the 9/11 presidency, forged of crisis, manifesting blind faith—a gamble taking on a logic of its own that before September 2001 would have been no logic at all. Bill Clinton wasn't wrong when he claimed during the campaign that Obama's candidacy represented a roll of the dice by an electorate that glimpsed, in the wake of its most disheartened moment since the dark collapse of the '60s, a new incarnation of the American promise, and that saw in Obama the embodiment of that promise.

A positively biblical seven years following 9/11, Obama wasn't the most idealistic candidate ever elected. To the contrary, for some he's pathologically pragmatic, more ready to accept a flawed result than fight for a better one. But his campaign awakened and was sustained by people's idealism more than any since Robert Kennedy's, and his election may have been the expression of those ideals more than any since John Kennedy's, though conservatives would fairly argue that Reagan was elected out of idealism as well. Conservatives might also fairly argue with the characterization of Obama's election as an expression of the ideals that were engendered by 9/11 while Bush's was an expression of the fears; they might insist not unreasonably that it's hard to make a country better if you haven't made it safe. But if the country's politics are symptomatic of its psyche, more difficult to dispute is that since Obama's election, some fault line has re-emerged (if it ever went away) with fundamentally opposing visions of the country on each side. It's by no means an unfamiliar fault line. It's been there since Jefferson and Hamilton squared off. But a country that gets the politics it deserves isn't very deserving right now, at a moment that feels abandoned by the nearly mystic sense of destiny, however great the gamble on a president who might have been, and for all we know may yet be, as exquisitely suited to the moment as he is unlikely.

With Obama's election, a fever broke. His presidency has been neutralized by the very catharsis of his election, which was a catharsis of everything felt on that September day ten years ago and after; if Obama's candidacy made people believe in the America of their dreams, then his presidency was bound to disappoint us. It can't help feeling like a betrayal. But the truth is that we're all complicit in what we've willfully misunderstood about Obama, each of us having chosen to misunderstand something different. When he said in the campaign that he wanted to get out of Iraq so he could double-down on Afghanistan, liberals nudged and winked to one another, assuming this was the tough talk in which Democratic nominees engage in order to win. Who then betrayed whom if Obama's Afghanistan policy has been true to his word? If conservatives figured it was Democratic boilerplate when Obama talked about passing health-care reform in his first term, at whom should the outrage be directed when Obama did as he said? It may be inevitable, and certainly is fitting, that the president of post-9/11 America reflects 300 million Americas as each of us perceives America to be, or as each of us thinks it should be. He's a partisan, he's a pushover. He's a radical, he's a sellout. He's rigid, he's vacillating; he's naive, he's expedient; he's ubiquitous, he's remote.

Obama ran as the post-9/11 president for everyone, but amid the cracked landscape of post 9-11, he risks becoming the president of no one. He ran not as a blue-state president succeeding the best president that red-state America ever had but as the united-states president who, in fact, would prove more committed to hunting down the criminals of September 11 than his predecessor ever was. We've always assumed that the America of our dreams is the same place, but it isn't anymore and maybe never was and never could have been, because in a way distinct from other nations, America is an act of imagination, and imagination never exists collectively; it exists singularly. For a moment, the most unifying American event of our time—9/11—appears to have left the country more divided than ever. Now, when Washington's skirmishes resemble the clashes of a decade and a half ago except for how much more ruthless they've become, it's as though the attacks never happened. Once that might have seemed a good thing; it's hard to believe that now. It's hard to be sure whether it's to Barack Obama's deficit, or George Bush's, or ours. The forces of al-Qaeda scatter, desperately on the run, and the Battle of 9/11 comes to an end. But the Battle of America goes on.